The invention discloses a grease gun filler, which comprises a barrel body (1), wherein, a top plate (12) and a bottom plate (13) are respectively arranged at the top and the bottom of the barrel body (1). The grease gun filler is characterized in that a middle bearing plate (2) is horizontally arranged at the middle upper part of the barrel body (1), a screw thread telescopic post (3) is vertically arranged at the middle upper part of the barrel body (1), a bull gear (7) is arranged at the top end, and the bottom end is fixedly connected with the bottom plate (13); the bull gear (7) is meshed with a pinion (9), the pinion (9), a spring sleeve (20) and a rotating device connecting rod (17) at the lower part are fixed into a whole, the spring sleeve (20) penetrates through a supporting frame (6), the rotating device connecting rod (17) penetrates through a rotating device outer wall (5) and the rotating device (10), a grease outlet on the middle bearing plate (2) and a grease outlet onthe side wall of the rotating device outer wall (5) are communicated with a grease gun hole(16) on the barrel body wall, and a hexahedron (22) at the top end of a spring (18) in the spring sleeve (20) is connected with a rocking bar (8), thus the grease gun filler has the advantages of convenience, quickness, grease economization, cleanliness, time conservation and high efficiency.